Guys, would you do this and if yes, why?

Would you text a girl 3/4 times a week if you had no interest in her? We worked together a long time ago (4 years) and he's kept in contact since. Even if I send him a funny/joke text he will find something to reply with. I don't know if its just friendship cause its not like we were good friends before. So what's the reason guys?

Updates:

His texts consist of asking about my day, how work is going, what I'm up to for the weekend. He texts on my bday and all the usual holidays and he'll send something that'll make me laugh

Well, even if he knows you're in a relationship, that doesn't mean he can simply turn off feelings for you if he has them. Maybe he does have a little more than just a friendship feeling, and assumes no harm can be done in a few messages.

Ignoring it may not help. And maybe you're already doing things that clue him in to your "small thing", already. Everyone has their own opinions on what level of flirting, if any, is okay in your situation, but that's still a far cry from throwing your relationship away.

Does it make you uncomfortable to think that maybe this guy has some feelings for you? Or did you just want to reassure yourself that you weren't imagining it?

Good question. I can't say it makes me uncomfortable or I need reassurance. I suppose its just that I'd be happier knowing he doesn't have feelings for me cause then I'd never wonder what if? Me I can control but I can't figure him out